Some conventionally suggested torque tools such as torque wrenches are designed to measure the tightening torque of clamp members such as bolts or nuts (hereinafter referred to as the bolt) as they are tightened. When the measured torque value obtained has reached a specified torque value, the torque tool informs, by the lamp being lit, the buzzer being sounded, or a slight impact, the operator that the measured torque value obtained has reached the specified torque value.
In Patent Document 1, disclosed is a torque wrench which is capable of determining whether the measured torque value has reached the specified torque value, and then indicating the determination result to the operator. This torque wrench is designed such that specified torque values required are pre-entered at the setting portion and then stored in the internal memory. Then, when actual tightening is performed, it is determined whether the measured torque value has reached the specified torque value, and the result is outputted by the buzzer being sounded or via an LED. Accordingly, this torque wrench makes it possible for the operator to check whether the tightening was conducted with the correct torque value, thus allowing a bolt or the like to be tightened with a required torque.
Furthermore, a torque wrench has been conventionally used to tighten consecutively a number of clamp members such as bolts. In this case, there could be some bolts that were not tightened with a correct torque value or not tightened at all by mistake.
To overcome such problems, it is necessary to collect data such as the measured torque value provided when a bolt is tightened or the number of bolts tightened, and control the bolt tightening data.
As a related prior art, there is a data transfer device disclosed in Patent Document 2. Patent Document 2 describes an invention that relates to the data transfer device configured as follows. That is, the data transfer device is composed of: a torque wrench which has a processing circuit for accumulating data such as the measured torque value provided when bolts are tightened or the number of bolts tightened, and a transmitter for transmitting the data by radio; an interface for receiving the data transmitted from the torque wrench and displaying the received data; and a personal computer connected to the interface to record the received data for data processing and data control.
This invention can collect and control data such as measured torque values, thereby checking based on the recorded measured torque values whether the tightening has been adequately performed. It is also possible to check based on the number of the tightened bolts recorded whether there is any one left untightened.    [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-289535    [Patent Document 2] Japanese Patent Application Laid-Open No. Hei. 8-118251